The continuing trend in the technology of data recording systems is to record data with higher densities and closely packed data bits or pulses so as to utilize the available storage surface of the record medium in an optimum manner. Apparently, as packing densities are incresed, there are attendant problems, such as pulse crowding, with resultant reduction in signal amplitude of adjacent bits, asymmetry of the data pulses, bit shift, and the like. Thus, during the readback process, low amplitude noise signals, sloping shoulder portions between data bits, and other spurious nondata voltages, may be detected and interpreted erroneously as data, or valid data may be distorted or lost.